Molding device for continuous casting equipped with agitator

ABSTRACT

There is provided a molding device for continuous casting equipped with an agitator that reduces the amount of generated heat, is easy to carry out maintenance, is inexpensive, and is easy to use in practice. The molding device for continuous casting equipped with an agitator of the invention receives liquid-phase melt of a conductive material, and a solid-phase cast product is taken out from the molding device through the cooling of the melt. The molding device includes a casting mold and an agitator provided so as to correspond to the casting mold. The casting mold includes a casting space that includes an inlet and an outlet at a central portion of a substantially cylindrical side wall, and a magnetic field generation device receiving chamber that is formed in the side wall and is positioned outside the casting space. The casting mold receives the liquid-phase melt from the inlet into the casting space and discharges the solid-phase cast product from the outlet through the cooling in the casting space. The agitator includes a magnetic field generation device having an electrode unit that includes first and second electrodes supplying current to at least the liquid-phase melt present in the casting space, and a permanent magnet that applies a magnetic field to the liquid-phase melt. The magnetic field generation device is received in the magnetic field generation device receiving chamber of the casting mold, generates magnetic lines of force toward a center in a lateral direction, makes the magnetic lines of force pass through a part of the side wall of the casting mold and reach the casting space, and applies lateral magnetic lines of force, which cross the current, to the melt.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.14/825,893, filed Aug. 13, 2015, which is a continuation of U.S. patentapplication Ser. No. 14/115,788, filed Nov. 5, 2013, which is a 371 ofInternational Patent Application No. PCT/JP2012/052412, filed Feb. 2,2012, which claims priority to Japanese Patent Application No.2011-246668, filed Nov. 10, 2011. The entire contents of U.S. patentapplication Ser. Nos. 14/115,788 and 14/825,893 are incorporated hereinby reference.

TECHNICAL FIELD

The present invention relates to a molding device for continuouscasting, which is equipped with an agitator, of continuous castingequipment that produces a billet, a slab or the like made of non-ferrousmetal of a conductor (conductive body), such as Al, Cu, Zn, or an alloyof at least two of them, or an Mg alloy, or other metal.

BACKGROUND

In the past, a melt agitating method to be described below has beenemployed in a casting mold for continuous casting. That is, for theimprovement of the quality of a slab, a billet, or the like, in aprocess for solidifying the melt, that is, when the melt passes throughthe casting mold, a moving magnetic field, which is generated from theoutside of the casting mold by an electromagnetic coil, is applied tothe melt present in the casting mold so that agitation occurs in themelt not yet solidified. A main object of this agitation is to degas themelt and to uniformize the structure. However, since the electromagneticcoil is disposed at the position close to high-temperature melt, thecooling of the electromagnetic coil and troublesome maintenance areneeded and large power consumption is obviously needed. In addition, thegeneration of heat from the electromagnetic coil itself caused by thepower consumption cannot be avoided, and this heat should be removed.For this reason, there are various problems in that the device itselfcannot but become expensive, and the like.

CITATION LIST—PATENT LITERATURE

Patent Literature 1: JP 9-99344 A

SUMMARY Technical Problem

The invention has been made to solve the above-mentioned problems, andan object of the invention is to provide a molding device for continuouscasting equipped with an agitator that reduces the amount of generatedheat, is easy to carry out maintenance, is inexpensive, and is easy touse in practice.

A molding device for continuous casting equipped with an agitatoraccording to an embodiment of the present invention is a device whichreceives liquid-phase melt of a conductive material and from which asolid-phase cast product is taken out through the cooling of the melt.The molding device includes a casting mold including a casting spacethat includes an inlet and an outlet at a central portion of asubstantially cylindrical side wall and a magnetic field generationdevice receiving chamber that is formed in the side wall and ispositioned outside the casting space, the casting mold receiving theliquid-phase melt from the inlet into the casting space and dischargingthe solid-phase cast product from the outlet through the cooling in thecasting space, and an agitator provided so as to correspond to thecasting mold, the agitator including a magnetic field generation devicehaving an electrode unit that includes first and second electrodessupplying current to at least the liquid-phase melt present in thecasting space, and a permanent magnet that applies a magnetic field tothe liquid-phase melt. The magnetic field generation device is receivedin the magnetic field generation device receiving chamber of the castingmold, generates magnetic lines of force toward a center in a lateraldirection, makes the magnetic lines of force pass through a part of theside wall of the casting mold and reach the casting space, and applieslateral magnetic lines of force, which cross the current, to the melt.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) is a view illustrating the entire structure of an embodimentof the invention, and FIGS. 1(b) and 1(c) are explanatory viewsillustrating the operation thereof.

FIG. 2(a) is an explanatory plan view taken along line II(a)-II(a) ofFIG. 1 and FIG. 2(b) is an explanatory view illustrating the bottom ofan outer casting mold.

FIG. 3(a) is an explanatory plan view of a magnetic field generationdevice 31 of an agitator 3, and FIG. 3(b) is an explanatory plan view ofa modified example thereof.

FIG. 4(a) is a plan view of another modified example of the magneticfield generation device 31 of the agitator 3, and FIG. 4(b) is anexplanatory plan view of a modified example thereof.

FIG. 5 is a view illustrating the entire structure of another embodimentof the invention.

FIG. 6 is a view illustrating the entire structure of another embodimentof the invention.

FIG. 7 is a view illustrating the entire structure of still anotherembodiment of the invention.

FIG. 8(a) is a view illustrating the entire structure of yet anotherembodiment of the invention, FIG. 8(b) is a cross-sectional view takenalong line VIII(b)-VIII(b) of FIG. 8(a), FIG. 8(c) is a cross-sectionalview taken along line VIII(c)-VIII(c) of FIG. 8(a), FIG. 8(d) is anexplanatory plan view of a magnetic field generation device, and FIG.8(e) is an explanatory plan view of a lid.

FIG. 9(a) is a view illustrating the entire structure of still anotherembodiment of the invention, FIG. 9(b) is a cross-sectional view takenalong line IX(b)-IX(b) of FIG. 9(a), and FIG. 9(c) is an explanatoryplan view of a magnetic field generation device.

FIG. 10 is a view illustrating the entire structure of yet anotherembodiment of the invention.

DETAILED DESCRIPTION

For deeper understanding of an embodiment of the invention, anelectromagnetic agitator, which uses electricity as power, of continuouscasting equipment in the related art will be described briefly.

In the related art, a fixed amount of melt M of non-ferrous metal isdischarged from a melt receiving box that is called a tundish and ispoured into a casting mold that is provided on the lower side. Coolingwater for cooling the casting mold is circulated in the casting mold.Accordingly, high-temperature melt starts to solidify from the outerperiphery thereof (a portion thereof close to the casting mold) from themoment that the high-temperature melt comes into contact with thecasting mold.

Since the melt, which is positioned at the central portion of thecasting mold, is distant from the wall of the casting mold that is beingcooled, the solidification of the melt positioned at the central portionof the casting mold is obviously later than that of the melt positionedat the peripheral portion of the casting mold. For this reason, twokinds of melt, that is, liquid (liquid-phase) melt and a solid(solid-phase) cast product are simultaneously present in the castingmold while being adjacent to each other with an interface interposedtherebetween. Further, generally, if melt is solidified too rapidly, gasremains in the cast product (product) having been changed into a solidand causes the quality of the product to deteriorate. For this reason,degassing is facilitated by the agitating of the melt that is not yetsolidified. The electromagnetic agitator, which uses electricity aspower, has been used for the agitating in the related art.

However, when such an electromagnetic agitator is used, there arevarious difficulties as described above.

Accordingly, the invention is to provide a molding device for continuouscasting equipped with an agitator that does not use the electromagneticagitator using electricity as power and uses permanent magnets.

An embodiment of the invention will be described in more detail below.

The entire structure of an embodiment of the invention is illustrated inFIG. 1(a). FIG. 2(a) is an explanatory plan view taken along lineII(a)-II(a) of FIG. 1(a), and mainly illustrates a part of an agitator 3and a casting mold 2, and FIG. 3(a) is an explanatory plan view of themagnetic field generation device 31 of the agitator 3.

As understood from FIG. 1(a), a device according to an embodiment of theinvention broadly includes a melt supply unit 1 that supplies melt M ofnon-ferrous metal of a conductor (conductive body), such as Al, Cu, Zn,or an ahoy of at least two of them, or an Mg alloy, or other metal; acasting mold 2 that receives the melt from the melt supply unit 1; andan agitator 3 that agitates the melt M present in the casting mold 2. Acentral portion of the casting mold 2 forms a so-called casting space2A(1) that includes an inlet 2A(1)1 and an outlet 2A(1)2.

The melt supply unit 1 includes a tundish (melt receiving box) 1A thatreceives melt M from a ladle (not illustrated) or the like. The melt Mis stored in the tundish (melt receiving box) 1A, inclusion is removedfrom the melt, and the melt M is supplied to the casting mold 2 from alower opening 1B of the tundish at a constant supply rate. Only thetundish (melt receiving box) 1A is illustrated in FIG. 1.

The casting mold 2 is adapted in this embodiment so that a columnarproduct P (billet) is taken out from the casting mold. For this purpose,the casting mold 2 is formed so as to have a substantially cylindricaldouble structure (of which the cross-section has a ring shape). That is,the casting mold 2 includes an inner casting mold 21 and an outercasting mold 22 that are fitted to each other. The inner casting mold 21is provided on the inside and made of a non-conductive material(non-conductive refractory material) such as graphite (carbon). Theouter casting mold 22 is provided on the outside and made of aconductive material (conductive refractory material), such as aluminumor copper.

As described in detail below, the magnetic field generation device 31 isassembled so as to be received within the side wall of the outer castingmold 22. Meanwhile, since the technical idea is the same as describedabove even when a prismatic product (slab) is taken out, the technicalidea of an embodiment to be described below can be applied as it is.Briefly, the shapes of components corresponding to a rectangular slab,which is a product, are merely changed.

The casting mold 2 further includes a water jacket 23 outside the outercasting mold 22.

The water jacket 23 is to cod the melt M that flows into the innercasting mold 21. That is, cooling water flows into the water jacket 23from an inlet (not illustrated) and is circulated in the water jacket23, the outer portion of the outer casting mold 22 is cooled by thecooling water, and the cooling water is discharged from an outlet (notillustrated). The melt M is rapidly cooled by the water jacket 23. Sincewater jackets having various known structures may be employed as thewater jacket 23, the detailed description thereof will not be providedhere.

In addition, a plurality of electrode insertion holes 2 a, 2 a, . . .into which electrodes 32A to be described below are inserted are formedat a predetermined interval on the circumference of the casting mold 2having the above-mentioned structure. The electrode insertion holes 2 aare formed so as to be inclined downward toward the center of thecasting mold 2. For this reason, if the surface of the melt M is lowerthan the upper openings of the electrode insertion holes 2 a even thoughthe melt M is contained in the casting mold 2, there is no concern thatthe melt M will leak to the outside.

As described above, briefly, the agitator 3 is provided so as to bebuilt in the side wall of the casting mold 2. The agitator 3 includes apermanent magnet type magnetic field generation device 31, and a pair ofupper and lower electrodes (positive and negative electrodes) 32A and32B.

In particular, as understood from FIG. 3(a), the magnetic fieldgeneration device 31 is formed in the shape of a ring (in a frameshape). The entire inner peripheral portion of the magnetic fieldgeneration device may be magnetized to an N pole, and the entire outerperipheral portion of the magnetic field generation device may bemagnetized to an S pole. Further, four portions of the inner and outerperipheral portions may be partially magnetized to an N pole and an Spole as illustrated in, for example, FIG. 3(a), respectively.

As understood from the following description, the magnetic fieldgeneration device 31 does not necessarily need to be formed in the shapeof a ring, and may be divided. That is, for example, as illustrated inFIG. 8(d), the cross-section of the magnetic field generation device maybe formed of a plurality of arc-shaped permanent magnet pieces (FIG. 4).As briefly described above, particularly, as understood from FIG. 1(a),the magnetic field generation device 31 is assembled in the outercasting mold 22.

In more detail, as understood from FIG. 1(a), the outer casting mold 22includes a magnetic field generation device receiving chamber 22 a whichis formed in the side wall thereof and has a ring-shaped cross-sectionand of which a lower portion forms a release port. The magnetic fieldgeneration device receiving chamber 22 a is also understood from FIG.2(b). FIG. 2(b) is a view of the outer casting mold 22 when the outercasting mold 22 is seen from below. In particular, as understood fromFIG. 1(a), the magnetic field generation device 31 also having aring-shaped cross-section is received in the magnetic field generationdevice receiving chamber 22 a, which has a ring-shaped cross-section andof which the lower portion is opened, from below so that the position ofthe magnetic field generation device in the vertical direction can beadjusted by movement. That is, the magnetic field generation device 31is provided so that the height of the magnetic field generation devicecan be adjusted in the magnetic field generation device receivingchamber 22 a by desired units (not illustrated). Accordingly, it ispossible to more efficiently agitate the melt M as described below byadjusting the height of the magnetic field generation device so as tocorrespond to liquid-phase melt M as understood from FIG. 1(a). Thelower opening of the magnetic field generation device receiving chamber22 a is closed by a ring-shaped lid 22B. The lid 22B may be formed so asto include discharge channels 22B(1) for discharging cooling water tothe outside such as a lid 22B of FIG. 8(a) to be described below.

As described above, the four portions of the magnetic field generationdevice 31 are magnetized and form pairs of magnetic poles 31 a, 31 a, .. . as illustrated in FIG. 3(a). That is, a portion of each of themagnetic poles 31 a, 31 a facing the inside of the ring-shaped magneticfield generation device is magnetized to an N pole, and a portionthereof facing the outside of the ring-shaped magnetic field generationdevice is magnetized to an S pole. Accordingly, magnetic lines of forceML generated from the N pole horizontally pass through the melt M thatis present in the casting mold 2.

The magnetization may be contrary to this. That is, the inner portionsof all magnetic poles may be magnetized to a certain pole and the outerportions thereof may be magnetized to an opposite pole. One ofadditional characteristics of the invention is that a plurality ofmagnetic poles are disposed at a plurality of positions surrounding themelt M, which is not yet solidified, as understood from FIG. 3(a).Accordingly, it is possible to improve the quality of the product P byagitating all the melt M with an electromagnetic force that is generatedaccording to Fleming's rule by magnetic lines of force and current asdescribed below. Therefore, the number of the magnetic poles is four inFIG. 3(a), but is not limited to four and may be arbitrary. Further, asdescribed above, the magnetic field generation device 31 does not needto be formed of a ring-shaped single body, and may be divided into aplurality of magnet bodies (magnet pieces), of which the number isarbitrary, as illustrated in FIG. 8(d).

In FIG. 1(a), current flows between the pair of electrodes 32A and 32Bthrough the melt M and a cast product (product) P. One electrode 32A maybe used, but a plurality of electrodes 32A may be used. In thisembodiment, two electrodes 32A are used. The electrodes 32A are formedin the shape of a probe.

The respective electrodes 32A are inserted into the above-mentionedelectrode insertion holes 2 a. That is, the electrodes 32A penetrateinto the casting mold 2 (the inner casting mold 21 and the outer castingmold 22) from the water jacket 23. Inner ends of the electrodes 32A areexposed to the inside of the inner casting mold 21, come into contactwith the melt M, and conduct electricity to the melt M. Outer ends ofthe electrodes 32A are exposed to the outside of the water jacket 23.The outer ends are connected to a power supply 34 that can supplyvariable direct current. The power supply 34 may have the function of anAC power supply as described below, and may have a function of changingfrequency. The electrodes 32A may be supported above the upper openingof the casting mold 2 without penetrating the side wall of the castingmold 2 so that the inner ends of the electrodes 32A are inserted intothe melt M from the surface of the melt M flowing into the casting mold2. The electrodes 32A may be electrically connected to the inner castingmold 21 made of graphite or the like.

The number of electrodes used as the electrodes 32A may be arbitrary,and an arbitrary number of the electrodes 32A may be inserted intoarbitrary electrode insertion holes of the electrode insertion holes 2a, 2 a, . . . .

In FIG. 1(a), the lower electrode 328 is provided so that the positionof the lower electrode 328 is fixed. The electrode 328 is formed of aroller type electrode. That is, the lower electrode 32B includes arotatable roller 32Ba at the end thereof. The roller 32Ba comes intopress contact with the outer surface of a columnar product P as a castproduct (a billet or a slab) that is extruded in a solid phase state.Accordingly, as the product P extends downward, the roller 32Ba isrotated. That is, when the product P is extruded downward, the product Pextends downward in FIG. 1 while coming into contact with the roller32Ba and rotating the roller 32Ba.

Accordingly, when a voltage is applied between the pair of electrodes32A and 32B from the power supply 34, current flows between the pair ofelectrodes 32A and 32B through the melt M and the product P. Asdescribed above, the power supply 34 is adapted so as to be capable ofcontrolling the amount of current flowing between the pair of electrodes32A and 32B. Therefore, it is possible to select current where theliquid-phase melt M can be agitated most efficiently in a relationshipwith the magnetic lines of force ML.

Next, the operation of the device having the above-mentioned structurewill be described.

In FIG. 1(a), a fixed amount of the melt M, which is discharged from thetundish (melt receiving box) 1A, is input to the upper portion of thecasting mold 2. The casting mold 2 is cooled through the circulation ofwater in the water jacket 23, so that the melt M present in the castingmold 2 is rapidly cooled and solidified. However, the melt M present inthe casting mold 2 has a two-phase structure where the upper portion ofthe melt is liquid (liquid phase), the lower portion thereof is solid(solid phase), and the upper and lower portions of the melt are adjacentto each other at an interface ITO. When passing through the casting mold2, the melt M is formed in the shape (a columnar shape in thisembodiment) corresponding to the shape of the casting mold. Accordingly,a product P as a slab or billet is continuously formed.

Further, since the permanent magnet type magnetic field generationdevice 31 is received in the side wall of the casting mold 2 asunderstood from FIG. 1(a) and the like, the magnetic field (magneticlines of force ML) of the magnetic field generation device reaches themelt M, which is present in the casting mold 2 in the lateral direction.In this state, when direct current is supplied to the lower electrode32B from the upper electrodes 32A by the power supply 34, the currentflows to the lower electrode 32B from the upper electrodes 32A throughthe melt (liquid phase) M of aluminum or the like and the product (solidphase) P. At this time, the current crosses the magnetic lines of forceML, which are generated from the permanent magnet type magnetic fieldgeneration device 31, substantially at right angles to the magneticlines of force. Accordingly, rotation occurs in the liquid-phase melt Min accordance with Fleming's left-hand rule. The melt M is agitated inthis way, so that impurities, gas, and the like contained in the melt Mfloat and so-called degassing is actively performed. Accordingly, thequality of the product a slab or a billet) P is improved.

Now, cooling capacity is increased or reduced by the water jacket 23 orthe like, the solidification rate of the melt M is changed and theinterface IT0 between the melt (liquid-phase) M and a product(solid-phase) P moves up and down according to this. That is, whencooling capacity is increased, the interface IT0 moves up like aninterface IT1 as illustrated in FIG. 1(b). When cooling capacity isreduced, the interface IT0 moves down like an interface IT2 asillustrated in FIG. 1(c). Further, it is preferable that the magneticfield generation device 31 be moved up and down according to thepositions of the interfaces IT0, IT1, and IT2 in order to efficientlyagitate the melt M. Accordingly, it is possible to obtain a product P asa high-quality product by reliably and efficiently agitating the melt M.For this purpose, the magnetic field generation device is adapted sothat the height of the magnetic field generation device 31 can beadjusted in the vertical direction according to the heights of theseinterfaces IT1 and IT2 as illustrated in FIGS. 1(b) and 1(c) and theposition of the magnetic field generation device 31 can be kept.Accordingly, it is possible to efficiently agitate the melt M asdescribed above.

On the contrary, the double structure of the casting mold 2 may beformed so that the inner portion of the casting mold is made of aconductive material and the outer portion thereof is made of anon-conductive material. In this case, at least the electrodes 32A maycome into electronically contact with the conductive material that formsthe inner portion of the casting mold. Even in this case, a magneticfield generation device receiving chamber 22 a may be formed in an outermember.

Further, the casting mold 2 may have not a double structure but a singlestructure. In this case, the casting mold 2 may be made of only aconductive material, and the electrodes 32A may conduct electricity tothe casting mold 2. The structure of the other electrode 32B may be thesame as described above.

On the contrary, the casting mold 2 may be made of only a non-conductivematerial. In this case, it is necessary to make the electrodes 32Aconduct electricity to the melt M present in the casting mold 2 bymaking the electrodes 32A penetrate into the casting mold 2 asillustrated in FIG. 1(a).

In these cases, obviously, a magnetic field generation device receivingchamber 22 a may be formed in a member having a single structure.

A magnetic field generation device 31A of FIG. 3(b) may be used insteadof magnetic field generation device 31 of FIG. 3(a). The magnetizationdirection of the magnetic field generation device 31A of FIG. 3(a) isopposite to that of the magnetic field generation device 31 of FIG.3(b). Both the magnetic field generation devices have the same function.

Further, magnetic field generation devices 31-2 and 31A-2 of FIGS. 4(a)and 4(b) may be used instead of the magnetic field generation devices 31and 31A of FIGS. 3(a) and 3(b). The magnetic field generation devices31-2 and 31A-2 of FIGS. 4(a) and 4(b) are adapted so that a plurality ofrod-like permanent magnets PM are fixed to the inside of a ring-shapedsupport (yoke) SP. These have the same function

Furthermore, an electrode, which includes the roller 32Ba at the endthereof, has been described as the lower electrode 32B in theabove-mentioned embodiment. However, the lower electrode does not needto necessarily include the roller 32Ba. Even though a product P iscontinuously extruded, the electrode 32B only has to conduct electricityto the product P and may employ various structures. For example, anelastic member having a predetermined length is used as the electrode32B and is bent, for example, so as to be convex upward or downward inFIG. 1, and the end of the elastic member comes into press contact withthe cast product P by the force of restitution. In this state, the castproduct P may be allowed to extend downward.

According to the above-mentioned embodiment of the invention, it ispossible to obtain the following effects.

In the embodiment of the invention, melt M that is not yet solidified isagitated to give movement, vibration, and the like to the melt M, sothat a degassing effect and the uniformization and refinement of thestructure are achieved.

In more detail, since the magnetic field generation device 31 is adaptedso as to be capable of being adjusted in the vertical direction in theembodiment of the invention, it is possible to obtain a high-qualityproduct P by reliably agitating the melt M. This is one of thecharacteristics of the invention as described above, and an idea, inwhich a magnetic field generation device 31 provided outside the castingmold is moved up and down in a device that is rapt to be hightemperature and large in size and hardly has an empty space as in theembodiment of the invention, itself is an idea that is not accustomed tothose skilled in the art. Accordingly, a technique of the invention, inwhich a magnetic field generation device is received in a casting moldand can be adjusted in the vertical direction, is a technical idea thatis peculiar to the inventor.

Further, since the magnetic field generation device 31 is formed in theembodiment of the invention so that a plurality of magnetic poles aredisposed at the positions surrounding the melt M or a ring-shaped magnetsurrounding the melt M is disposed, it is possible to efficientlyagitate all the melt M with an electromagnetic force that is generatedaccording to Fleming's rule by magnetic lines of force and current.Accordingly, it is possible to obtain a product P as a high-qualityproduct. That is, in the embodiment of the invention, it is possible toefficiently agitate the melt M by making the best use of anelectromagnetic force that is generated according to Fleming's rule. Inaddition, the axis of the rotation of the melt M, which is caused bythis agitating of the melt, is an axis parallel to the center axis ofthe product P in FIG. 1(a). Accordingly, it is possible to obtain ahigh-quality product as a product P by making the rotational drive ofthe melt M reliable.

Moreover, in the embodiment of the invention, melt M is agitated with anelectromagnetic force that is generated according to Fleming's rule andis agitated by the cooperation between small current flowing in the meltM and a magnetic field generated from the magnetic field generationdevice 31. Accordingly, it is possible to obtain a device that stablyand continuously expects reliable agitation unlike melting and agitationperformed using the intermittent flow of large current according to theprinciple of arc welding or the like and has low noise and highdurability.

It is obvious that the above-mentioned effects are obtained from allembodiments to be described below.

Meanwhile, direct current has been supplied between the electrodes 32Aand 32B in the above description, but alternate current having a lowfrequency of about 1 to 5 Hz may be supplied from the power supply 34.In this case, the melt M does not rotate but repeatedly vibratesaccording to the cycle thereof in the relationship with a magnetic fieldthat is generated from the magnetic field generation device 31.Impurities are removed from the melt M even by the vibration. Thismodified example may be applied to all embodiments to be describedbelow. In this case, it is obvious that a power supply having a functionof changing frequency is employed as the power supply 34.

Further, the realization of mass production facilities is currentlyrequired in the industry. It is essential to realize a casting mold thatis as small as possible when mass production is considered.

Here, the electromagnetic agitating device in the related art can copewith a case where several slabs or billets are produced at one time.However, at present, there is a demand for the production of billets ofwhich the number exceeds 100. The electromagnetic agitator in therelated art cannot cope with this demand.

However, permanent magnets are used as the magnetic field generationdevice in the device of the invention. For this reason, it is possibleto make the device very compact in comparison with the electromagneticagitator that is supplied with large current. Accordingly, it ispossible to sufficiently realize a molding device for a mass productionfacility. Further, since the magnetic field generation device ispermanent magnet type, it is possible to obtain a device having effects,such as no heat generation, power saving, energy saving, and lessmaintenance, as a magnetic field generation device.

FIG. 5 illustrates another embodiment of the invention.

More current is supplied to this liquid-phase melt M to generate alarger electromagnetic force so that the melt M is rotationally driven.

This embodiment is different from the embodiment of FIG. 1(a) in thestructure of a casting mold 2A. Other structures are substantially thesame as FIG. 1(a). Accordingly, the detailed description thereof willnot be repeated here.

That is, the casting mold 2A of this embodiment includes a substantiallycylindrical casting mold body 2A1. The casting mold body 2A1 includes acircumferential groove 2A1(a) that is formed on the inner peripheralsurface thereof. An insulating film 2A2 is formed on the inner surface(the peripheral surface and the bottoms) of this groove, and an embeddedlayer 2A3 is formed by embedding the same conductive material as thecasting mold body 2A1 on the insulating film 2A2. An insulating layerportion is formed of the insulating film 2A2 and the embedded layer 2A3.The insulating layer portion is formed on a part of the inner surface ofthe casting mold, and functions as a portion that does not allow theflow of current from the casting mold.

This insulating layer portion is formed on a slightly lower portion ofthe inner surface of the casting mold body 2A1.

Accordingly, current is hardly allowed to flow to the cast product Pfrom the insulating layer portion of the casting mold body 2A1, that is,a portion adjacent to the cast product P.

In addition, a terminal 2A4 is provided on the outer periphery of thecasting mold body 2A1. Power can be supplied to the casting mold 2A fromthe power supply 34 through this terminal 2A4.

When a voltage is applied between the terminal 2A4 and the electrode 32Bby the power supply 34 in the device having this structure, currentflows in the casting mold body 2A1, the melt M, and the cast product P.Since current does not flow in the insulating film 2A2 and the embeddedlayer 2A3 at this time, larger current flows in the melt M. Accordingly,a larger electromagnetic force, which allows the melt M to be agitated,is obtained.

FIG. 6 illustrates still another embodiment.

This embodiment is a modification of the embodiment of FIG. 1(a).

This embodiment is different from the embodiment of FIG. 1(a) in thedisposition of the upper electrodes 32A of FIG. 1(a). That is, in thisembodiment, one electrode 32A0 is disposed or a plurality of electrodes32A0 are disposed annularly, these electrodes 32A0 are supported byarbitrary units other than the casting mold 2A and the like (the castingmold 2A and the water jacket 23), and a lower end portion of each of theelectrodes 32A0 is inserted into the melt M. Accordingly, it is possibleto adjust the length of the lower end portion, which is inserted intothe melt M, of the electrode 32A0 with large degree of freedomregardless of the casting mold 2A and the like. Moreover, obviously, anormal mold may be used as the casting mold 2A or the like, andelectrode insertion holes 2 a for electrodes 32A1 do not need to beformed in the casting mold 2A or the like. Therefore, it is alsopossible to prevent the increase in the manufacturing costs of these.

Other structures are the same as the embodiment of FIG. 1(a).

FIG. 7 illustrates yet another embodiment.

This embodiment may be regarded as a modified example of the embodimentof FIG. 6.

The embodiment of FIG. 7 is assumed as a device that can be operatedwhen melt M is poured into a casting mold 2A, which is provided on thelower side, from a tundish (melt receiving box) 1A, which is provided onthe upper side, as continuous melt with no interruption. That is, it isassumed that the melt M present in the tundish (melt receiving box) 1Aand the melt M present in the casting mold 2A are integrally connectedto each other.

In FIG. 6, the electrodes 32A0 are inserted into the melt M present inthe casting mold 2. However, in FIG. 7, an electrode 32A1 is supportedby arbitrary units so as to be inserted into the melt M present in thetundish (melt receiving box) 1A on the premise of the above-mentionedcase. Accordingly, it is possible to obtain the same advantage as theabove-mentioned embodiment of FIG. 6. In addition, it is possible to setand adjust a distance between the tundish (melt receiving box) 1A andthe casting mold 2A or the like regardless of the electrode 32A1.

Other structures are substantially the same as FIG. 6.

FIGS. 8(a) to 8(d), FIGS. 9(a) to 9(c), and FIG. 10 illustrate otherembodiments of the invention, respectively.

The same members of these embodiments as the members of theabove-mentioned embodiment are denoted by the same reference numeralsand the description thereof will not be repeated.

In these embodiments, a water jacket for cooling does not need to beseparately provided, a water flow chamber 22 a(2), which functions asboth a cooling chamber and a magnetic field generation device receivingchamber, is formed in the side wall of a casting mold 2, that is, theside wall of the outer casting mold 22, and a magnetic field generationdevice 31 as a permanent magnet is received in the water flow chamber 22a(2) so that the position of the magnetic field generation device can beadjusted in the vertical direction.

Meanwhile, a magnetic field generation device receiving space (magneticfield generation device receiving chamber) 22 a(2) illustrated in FIG.8(c) may be divided so as to receive a plurality of permanent magnetpieces 31A, which are illustrated in FIG. 8(d) and disposed at apredetermined interval, respectively. For example, the magnetic fieldgeneration device receiving space may be formed of a plurality ofpartial magnetic field generation device receiving chambers having anarc-shaped cross-section.

First, a device of manufacturing a billet of the embodiment illustratedin FIGS. 8(a) to 8(e) will be described.

That is, as understood from FIG. 8(a), the outer casting mold 22includes a water flow chamber 22 a(2) that is opened downward and has aring-shaped cross-section, and the water flow chamber 22 a(2) ishermetically-sealed by a lid 22B(1). FIG. 8(b) is a view illustratingthe inner casting mold 21 and the outer casting mold 22 taken along lineVIII(b)-VIII(b) from below when the lid 22B(1) is removed. This lid22B(1) forms a part of the casting mold 2.

As understood from FIG. 8(a), a magnetic field generation device 31,which is formed of a plurality of permanent magnet pieces 31A (FIG.8(c)) having an arc-shaped cross-section, is received in the ring-shapedwater flow chamber 22 a(2) serving as a magnetic field generation devicereceiving space (receiving chamber) so as to be capable of beingadjusted in the vertical direction. That is, the water flow chamber(cooling chamber) 22 a(2) functions as both a cooling water flow chamberand a magnetic field generation device receiving chamber. A plan view ofthese permanent magnet pieces 31A is illustrated in FIG. 8(d). The innerportion of each of the permanent magnet pieces 31A is magnetized to an Npole and the outer portion thereof is magnetized to an S pole. Themagnetization may be contrary to this. That is, the magnetic fieldgeneration device 31 is provided so that the height of the magneticfield generation device can be adjusted in the water flow chamber 22a(2) by arbitrary units (not illustrated). Accordingly, it is possibleto more efficiently agitate the melt M by adjusting the height of themagnetic field generation device so as to correspond to liquid-phasemelt M as described above.

The lower opening of the water flow chamber 22 a(2) is dosed by theabove-mentioned ring-shaped lid 22B. A plan view of the lid 22B isillustrated in FIG. 8(e). As understood from FIGS. 8(e) and 8(a), aplurality of discharge channels 22B(1) for cooling water are formed inthe lid 22B(1). As understood from FIGS. 8(a) and 8(e), the plurality ofdischarge channels 22B(1) include a plurality of inlets 22B(1)a 1 thatare opened to the upper surface of the lid 22B, and include outlets22B(1)a 2 on the peripheral surface of the lid 22B. Accordingly, codingwater present in the water flow chamber 22 a(2) enters from theplurality of inlets 22B(1)a 1, flows out of the outlets 22B(1)a 2, andis jetted to the outer periphery of the product P to cod the product P.That is, cooling water enters the water flow chamber 22 a(2) from inlets(not illustrated), is circulated in the water flow chamber while coolingthe product, and is discharged while being jetted to the outside fromthe discharge channels 22B(1).

Since the operation of the above-mentioned device of FIGS. 8(a) to 8(e)is the same as that of the above-mentioned embodiment, the descriptionthereof will not be repeated.

Meanwhile, the magnetic field generation device 31 has been formed ofthe plurality of permanent magnet pieces 31A in the above-mentionedembodiment of FIGS. 8(a) to 8(e). However, it is obvious that themagnetic field generation device may be integrally formed as in FIG.3(a). Further, the water flow chamber 22 a(2) serving as the magneticfield generation device receiving space is formed in a circumferentialshape as understood from FIG. 8(b). However, the water flow chamber isnot limited to this shape, and may be formed of a plurality of cellchambers that are divided in the circumferential direction and have anarc-shaped cross-section. It is preferable that cooling water can flowin each cell chamber and the permanent magnet piece 31A be received ineach cell chamber so as to be capable of moving up and down.

In the device of FIGS. 8(a) to 8(e), the magnetic field generationdevice 31 is not provided outside the casting mold 2, and a cavity(water flow chamber 22 a(2)) is formed in the casting mold 2 (outercasting mold 22) and the magnetic field generation device 31 is receivedin the cavity. Accordingly, it is possible to obtain the followingcharacteristics.

A permanent magnet, which is small and has a small capacity, may be usedas the magnetic field generation device 31.

That is, if the magnetic field generation device 31 is provided outsidethe casting mold, it is inevitable that a distance between the magneticfield generation device 31 and the melt M is slightly increased.However, since the magnetic field generation device is built in thecasting mold 2 in this embodiment, the distance between the magneticfield generation device 31 and the melt M is reduced. Accordingly, apermanent magnet, which is small and has a small capacity, may be usedto obtain the same agitating performance.

It is possible to significantly improve a working property.

That is, when this device is operated, a plurality of inspectors shouldbe positioned around the device to perform various kinds of measurement,nondestructive inspection, and the like and should perform such themeasurement and the like for the check of a product P. However, in thecase of the magnetic field generation device that is provided outside,the increase in size and volume cannot be avoided and it cannot bedenied that it is difficult to perform such the measurement since astrong magnetic field is generated. However, since the magnetic fieldgeneration device 31 is provided in the casting mold 2 in thisembodiment, a volume is not increased and the intensity of a magneticfield emitted to the outside is reduced. For this reason, it is easy toperform various kinds of measurement and the like.

It is possible to significantly improve productivity.

That is, it is possible to reduce time required for the above-mentionedmeasurement and the like. As a result, it is possible to increase themanufacturing rate of a product P per unit time.

It is possible to reduce size.

That is, since the magnetic field generation device 31 is a built-intype, it is possible to provide a device that is small as a whole asmuch as that.

It is possible to save a space of an installation location.

That is, since the magnetic field generation device 31 is a built-intype when the device is regarded as a device manufacturing the sameproduct P although being the same as described above, the size of thedevice is reduced as a whole. Accordingly, it is possible to install thedevice even at a narrow place. As a result, flexibility is obtained inthe usefulness of the device.

The above-mentioned effects will be described below from a differentstandpoint.

When a product P is manufactured by this device, for example, five orsix workers gather around the device and should perform high-densityworks (works for monitoring and preventing the leakage of melt, worksfor monitoring and preventing the jet of melt, and the like) in a shorttime. When these works are performed by a plurality of workers, aworking property is good in the built-in type device of this embodimentas compared to a case where the magnetic field generation device 31 isprovided outside so as to protrude. That is, since the externalappearance of the device has the same dimensions as the dimensions of adevice that does not include the magnetic field generation device 31that is a device in the related art, the device of this embodiment isvery easy to use at the work site.

Further, it is preferable that the magnetic field generation device 31be close to the melt M as much as possible in order to reliably apply amagnetic field to the melt M, and this is realized in a built-in type.

When the magnetic field generation device 31 is provided outside, theinfluence of a magnetic field on various measuring instruments such astemperature sensors should be considered. However, since the influencethereof is reduced in a built-in type, a built-in type is moreadvantageous in measurement. That is, when a product P, such as a slabor a billet, is manufactured, the measurement, management, and the likeof temperature in several positions are very important to maintain thequality of a product. This embodiment is very advantageous in themeasurement of temperature and the like.

If a built-in type magnetic field generation device as in thisembodiment is used instead of the magnetic field generation deviceprovided outside, the size, weight, and volume of a device may bereduced when the same magnetic field is applied to the melt M.Accordingly, the device is easy to use. That is, since the respectivecomponents of this device are consumables, the respective components ofthis device need to be replaced whenever a predetermined operation timehas passed. However, since the magnetic field generation device 31 issmall and light, a work for replacing the magnetic field generationdevice and the like are very easily performed.

Since a work at the device of this embodiment is a work that isperformed at a so-called high temperature of about 700° C., the work isvery dangerous for a worker. However, a magnetic field generationdevice, which is small and of which the intensity of a magnetic field islow, may be used as the magnetic field generation device 31. Further, atool, which is used for the adjustment, maintenance, and the like of thedevice, is generally a ferromagnetic body made of iron and safety shoesand the like are also made of iron. However, if a magnetic field of themagnetic field generation device 31, which is emitted by the outside, isreduced a little, the safety of a security officer, a worker, ameasuring person, and the like is ensured.

It is obvious that the effects described above with reference to FIGS.8(a) to 8(e) are mentioned in not only the device of FIG. 1 and the likebut also devices for manufacturing a slab that are to be described belowand illustrated in FIGS. 9(a) to 9(c) and 10.

FIGS. 9(a) to 9(c) illustrate a device for manufacturing a slab.However, the basic technical idea of the device is the same as describedabove except that a billet has a circular shape and a slab has arectangular shape. Accordingly, the same members are denoted by the samereference numerals and the description thereof will not be repeated.

A difference will be described below.

The weight of a slab as a product P is very heavy. For this reason, abillet can be pulled in the horizontal direction, but a slab as aproduct P is not obtained unless taken out in the vertical direction.For this reason, a pedestal 51 is prepared, and a product P is taken outwhile riding the pedestal 51 and being gradually pulled downward. Alower electrode 32B is embedded in the pedestal 51. A magnetic fieldgeneration device 31 is illustrated in FIGS. 9(b) and 9(c). FIG. 9(b) isa cross-sectional view taken along line IX(b)-IX(b) of FIG. 9(a), andFIG. 9(c) is a plan view of the magnetic field generation device 31.Here, the magnetic field generation device 31 uses four permanent magnetpieces 31A and forms two pairs facing each other, but may use any onepair.

FIG. 10 illustrates a modified example of FIG. 9(a).

In FIG. 10, a pair of electrodes 32A and 32B is used while beinginserted into melt M. The inventor confirmed by an experiment that themelt M is agitated even though the electrodes 32A and 32B are used inthis way. That is, even though the pair of electrodes 32A and 32B isemployed as illustrated in FIG. 10, the magnetic lines of forcegenerated from a magnetic field generation device 31 and current flowingbetween the pair of electrodes 32A and 32B flow in various paths in themelt M and generate an electromagnetic force according to Fleming'srule.

I/We claim:
 1. A method for casting nonferrous metal, the methodcomprising: shaping nonferrous metal by moving the nonferrous metalthrough a casting mold in a casting direction; passing electricalcurrent between a first electrode electrically connected to the shapednonferrous metal at a first location and a second electrode electricallyconnected to the shaped nonferrous metal at a second location spacedapart from the first location; and applying a magnetic field to aportion of the shaped nonferrous metal between the first location andthe second location, wherein passing the electrical current and applyingthe magnetic field together agitate the portion of the shaped nonferrousmetal between the first location and the second location.
 2. The methodof claim 1 wherein: passing the electrical current includes passingdirect current; and passing the electrical current and applying themagnetic field together agitate the portion of the shaped nonferrousmetal between the first location and the second location by causing theportion of the shaped nonferrous metal between the first location andthe second location to rotate about an axis parallel to the castingdirection.
 3. The method of claim 1 wherein: passing the electricalcurrent includes passing alternating current; and passing the electricalcurrent and applying the magnetic field together agitate the portion ofthe shaped nonferrous metal between the first location and the secondlocation by causing the portion of the shaped nonferrous metal betweenthe first location and the second location to vibrate.
 4. The method ofclaim 1 wherein the second location is spaced apart from the firstlocation in the casting direction.
 5. The method of claim 1 whereinapplying the magnetic field includes applying the magnetic field via oneor more permanent magnets.
 6. The method of claim 5 wherein applying themagnetic field includes applying the magnetic field while the one ormore permanent magnets are stationary.
 7. The method of claim 5 wherein:the casting mold defines a casting space having a round cross-sectionalshape in a plane perpendicular to the casting direction; the one or morepermanent magnets are disposed around the shaped nonferrous metal in aplane perpendicular to the casting direction; and applying the magneticfield includes applying the magnetic field via one or more curved facesof the one or more permanent magnets.
 8. The method of claim 5 wherein:the casting mold defines a casting space having a rectangularcross-sectional shape in a plane perpendicular to the casting direction;the one or more permanent magnets are disposed around the shapednonferrous metal in a plane perpendicular to the casting direction; andapplying the magnetic field includes applying the magnetic field via oneor more straight faces of the one or more permanent magnets.
 9. Themethod of claim 5, further comprising adjusting a position of the one ormore permanent magnets in the casting direction relative to the castingmold.
 10. The method of claim 1 wherein applying the magnetic fieldincludes applying the magnetic field such that the same poleshorizontally oppose one another via the shaped nonferrous metal.
 11. Themethod of claim 1 wherein applying the magnetic field includes applyingthe magnetic field such that field lines of the magnetic field cross theelectrical current at right angles.
 12. A casting system, comprising: acasting mold configured to continuously shape nonferrous metal movingthrough the casting mold in a casting direction; a first electrodepositioned to be electrically connected to the shaped nonferrous metalat a first location; a second electrode positioned to be electricallyconnected to the shaped nonferrous metal at a second location spacedapart from the first location; a power supply configured to passelectrical current through a portion of the shaped nonferrous metalbetween the first location and the second location via the firstelectrode and the second electrode; and a magnetic field generationdevice configured to apply a magnetic field to the portion of the shapednonferrous metal between the first location and the second location. 13.The casting system of claim 12 wherein: the power supply is configuredto pass direct current through the portion of the shaped nonferrousmetal between the first location and the second location via the firstelectrode and the second electrode; and the power supply and themagnetic field generation device are collectively configured to agitatethe portion of the shaped nonferrous metal between the first locationand the second location by causing the portion of the shaped nonferrousmetal between the first location and the second location to rotate aboutan axis parallel to the casting direction.
 14. The casting system ofclaim 12 wherein: the power supply is configured to pass alternatingcurrent through the portion of the shaped nonferrous metal between thefirst location and the second location via the first electrode and thesecond electrode; and the power supply and the magnetic field generationdevice are collectively configured to agitate the portion of the shapednonferrous metal between the first location and the second location bycausing the portion of the shaped nonferrous metal between the firstlocation and the second location to vibrate.
 15. The casting system ofclaim 12 wherein the magnetic field generation device includes one ormore permanent magnets though which the magnetic field generation deviceis configured to apply the magnetic field to the portion of the shapednonferrous metal between the first location and the second location. 16.The casting system of claim 15 wherein: the casting mold defines acasting space having a round cross-sectional shape in a planeperpendicular to the casting direction; the one or more permanentmagnets are positioned to be disposed around the shaped nonferrous metalin a plane perpendicular to the casting direction; and the one or morepermanent magnets include one or more curved faces through which themagnetic field generation device is configured to apply the magneticfield to the portion of the shaped nonferrous metal between the firstlocation and the second location.
 17. The casting system of claim 15wherein: the casting mold defines a casting space having a rectangularcross-sectional shape in a plane perpendicular to the casting direction;the one or more permanent magnets are positioned to be disposed aroundthe shaped nonferrous metal in a plane perpendicular to the castingdirection; and the one or more permanent magnets include one or morestraight faces through which the magnetic field generation device isconfigured to apply the magnetic field to the portion of the shapednonferrous metal between the first location and the second location. 18.The casting system of claim 15 wherein: an inner side of the one or morepermanent magnets is magnetized to one of N and S poles; and an outerside of the one or more permanent magnets is magnetized to the other ofN and S poles such that the same poles horizontally oppose one anothervia the shaped nonferrous metal.
 19. The casting system of claim 15wherein the one or more permanent magnets are adjustably mounted to thecasting mold such that a position of the one or more permanent magnetsin the casting direction can be adjusted relative to the casting mold.20. The casting system of claim 15 wherein: the casting mold includes awater jacket; and the one or more permanent magnets are disposed withinthe water jacket.